DEMO Site 4: Llobregat River infiltration basins, Sant Vicenç dels Horts, Catalonia, Spain
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| Infiltration pond filling | Placement of an organic reactive layer |
The challenge in this study area is given by the dual need to (i) increase the strategic groundwater reserves in the Llobregat aquifer in order to supply Barcelona's metropolitan area, and (ii) at the same time to improve the quality of the groundwater in the aquifer:
Quantitative issues - MAR to increase direct recharge that has been diminished due to the changes in soil uses (impermeabilization of a number of areas).
Qualitative issues - Studying whether an active layer located in the bottom of an infiltration pond may enhance the degradation of certain organic contaminants.
Artificial aquifer recharge is facilitated at this DEMO through surface infiltration ponds. The site includes a sedimentation and an infiltration pond. Water for recharge is diverted from the Llobregat River. Recovery is not done at the same site, but a number of extraction wells are located downgradient. Since the river and the aquifer are disconnected, no infiltrated water eventually reaches the river.
The area is heavily instrumented. Outside the area there are several piezometers (some of them multilevel) and a pumping well. Within the infiltration pond some instrumentation has been placed in order to analyze the infiltrating water; these include temperature sensors, suction caps and a lysimeter.
Recently an innovative MAR technology was implemented in the field: a vegetal compost-made reactive organic layer. During the first two years after the layer installation in the infiltration pond, an improvement in the elimination of some pollutants present in the recharge water was observed, leading to a positive impact on the quality of the recharged water. The impact of the organic layer at large times has not been assessed. The work proposed involves the development of biogeochemical models to account for the processes taking place within the soil and the aquifer in an integrated platform (i.e., decantation and infiltration of suspended solids, chemical precipitation and biological degradation processes). This involves additional site characterization, with a number of hydraulic and tracer tests to find and map heterogeneous patterns. Infiltration can be mapped also using some geophysical imaging that could be included in the modelling process.
Emphasis will be placed in the description of processes occurring right below the pond, such as denitrification and reduction of organic matter, boosted by the microbial activity at the non-saturated zone. The immediate effect would be the release of greenhouse effect gases from the pond. Since measurements of emissions are difficult at the site, a prototype of an aquifer will be prepared at the lab and tested for gas emissions.
MARSOL
Demonstrating Managed
Aquifer Recharge as a
Solution to Water Scarcity
and Drought
An EU FP7 Project
Coordination & Contact:
Prof. Dr. Christoph Schüth
Darmstadt Technical University
Institute of Applied Geosciences
Schnittspahnstr. 9
64287 Darmstadt
Germany
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The MARSOL project receives funding from the European Union's Seventh Framework Programme for Research, Technological Development and Demonstration under grant agreement no 619120. This project website reflects only the authors' views and the European Union is not liable for any use that may be made of the information contained therein. |